B340L MPS [Monolithic Power Systems], B340L Datasheet - Page 4

• Manufacturer Part Number: B340L
• Description: 2A, 32V, 330KHz Step-Down Converter
• Manufacturer: MPS [Monolithic Power Systems]

OPERATION
The MP1591 is a current mode step-down
regulator. It regulates input voltages from 6.5V
to 32V down to an output voltage as low as
1.230V and is able to supply up to 2A of load
current.
The MP1591 uses current-mode control to
regulate the output voltage. The output voltage
is measured at FB through a resistive voltage
divider and amplified through the internal error
amplifier.
transconductance error amplifier is presented at
COMP where a network compensates the
regulation control system.
MP1591 Rev. 2.3
9/27/2006
REF
EN 7
IN 2
8
COMPARATOR
FREQUENCY
2.60V/
2.35V
FOLDBACK
1.2V
The
+
--
--
+
output
5V
COMPARATOR
COMPARATOR
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
SHUTDOWN
REGULATORS
PROTECTION
LOCKOUT
+
--
INTERNAL
THERMAL
0.7V
current
FB
5
Figure 1—Functional Block Diagram
OSCILLATOR
1.230V
35/330KHz
© 2006 MPS. All Rights Reserved.
--
+
of
AMPLIFIER
www.MonolithicPower.com
ERROR
SLOPE
COMP
the
CLK
MP1591 – 2A, 32V, 330KHz STEP-DOWN CONVERTER
COMP
6
AMPLIFIER
CURRENT
+
--
SENSE
The voltage at COMP is compared to the switch
current measured internally to control the output
voltage.
N-Channel MOSFET switch to step-down the
input voltage to the regulated output voltage.
Since the MOSFET requires a gate voltage
greater than the input voltage, a boost capacitor
connected between SW and BS drives the gate.
The capacitor is internally charged while SW is
low. An internal 10Ω switch from SW to GND is
used to insure that SW is pulled to GND when
the switch is off to fully charge the BS capacitor
COMPARATOR
CURRENT
R
S
The
1.8V
+
--
Q
Q
converter
uses
an
M1
M2
internal
1
3
4
BS
SW
GND
4